Hello anatomy colleagues this is Dr. Alsup and in this video
we will explore the spaces both real and potential created by the cranial meninges.
And some of the clinical considerations specifically the hematomas or hemorrhages,
those words are used interchangeably often that will occur in these areas.
So hopefully by the end of this you can draw your own diagram of the meningeal spaces associated
with the skull and where an epidural a subdural and a subarachnoid hemorrhage or hematoma will occur.
Of note here we are obviously going to focus more on the anatomical basis of these. So where it's
located between which meningeal layers and less about how these present clinically or what to do
about it if they do occur this will certainly be covered in other lectures during the neuro portion.
So a reminder on what is the difference between a real and potential space. A real or actual space
is going to be naturally occurring. So sometimes it's visible but it certainly will be naturally
occurring, whereas a potential space is typically not naturally occurring. So a potential space
can become a real or actual space with the entrance of say blood or other
fluids air that will separate normally adherent structures or normally adherent meninge layers.
So let's discuss some of these spaces in the clinical considerations
in these areas starting with the most superficial which is the epidural space.
The epidural space is going to be located between the bone as you can see here and the
periosteal dura so here's the periosteal dura here is the bone and here is the epidural space.
And this is a potential space hopefully you recall that in the spinal region
the epidural space is actually an actual real space that's often filled with epidural fat
but in the cranial region this epidural space can become a real space in cases
of an epidural sometimes referred to as extradural hematoma or hemorrhage. So you can see here
that blood is located between the bone and the periosteal dura. And this blood is typically
arterial and origin and most commonly a branch of the middle meningeal artery will tear which
as its name suggests will be supplying blood to the meninges. So if you ever hear the term epidural
hematoma is located in this region. Obviously you can see how this can lead to compression of the
brain and a whole slew of presentations can occur to be discussed in upcoming clinical lectures.
Okay next we have the subdural space which is going to be located between the dura specifically
the meningeal dura and the arachnoid mater so you can see that located here in this kind of
yellow color. This is another potential space that can become an actual space where escaped
blood which is typically venous in origin will separate these layers that are typically adhered.
So this right here is going to be the subdural hematoma here is your meningeal dura here is
your arachnoid and then you have typically venous blood that will enter into this region. So this is
what occurs in a subdural or sometimes referred to as a dural border hemorrhage or hematoma. And
lastly we have the trusty subarachnoid space which i hope at this point we understand is an actual
or real space that in a healthy individual has lots of structures running through it
typically so you have cerebral spinal fluid as well as neurovasculature. However there can also
be hemorrhages occurring in this space as well due to many or multiple causes such as head trauma
but most commonly a subarachnoid a hematoma occurs because of a ruptured
sometimes referred to as a ruptured saccular aneurysm you will discuss brain aneurysm soon.
But the blood will escape and be held within the subarachnoid space which is between the arachnoid
and the pia mater and so it'll be held in that space there and this is referred to as
a subarachnoid hematoma or hemorrhage. Excellent we have reached the summary slide and hopefully
you feel comfortable with the anatomical spaces both actual or potential associated with meninges
and where these hematomas or hemorrhages can occur these more common ones. Please take time to review
and reach out if you have any questions. Please have an excellent rest of your day